V-six engines



oct. 25, 1960 Filed Dec. 1, 1958 C. H. BOUVY V-SIX ENGINES 2 VSheets-Sheet 1 IN VEN TOR. CMQ/SWAN# 5oz/Vy TTO/F/YEY Oct. 25, 1960 c. H. BouvY 2,957,455

V-SIX ENGINES Filed Dec. 1, 1958 2 Sheets-Sheet 2 OFFSET 'A Tro/P/vfy United States Patent C V-SIX ENGINES Christiaan H. Bouvy, Bloomfield Township, Mich., assignor to John Dolza, Fenton, Mich.

Filed Dec. 1, 1958, Ser. No. 777,362

Claims. (Cl. 121-120) This invention relates to V-six type internal combustion engines, and in particular to improved crank pin arrangement and balancing means for V-six engines wherein the included angle of the two cylinder banks, commonly called the V-angle or block angle, deviates from the normal commonly used 60 degrees.

In a V-six engine, if the crank pin or crank angle is made equal to 180 degrees minus twice the V-angle, the primary unbalanced couples in the two cylinder banks produce a rotating couple of constant magnitude which can be neutralized by the use of suitable crankshaft counterweights.

For example, if the V-angle in a V-six engine were made 62 degrees instead of the usual 60 degrees, a crank angle of 180 degrees minus 2X62degrees, or a 56 degree crank angle, would be necessary to satisfy the requirement for primary balance. However, sucha crank angle deviation from the normal crank angle of 60 degrees normally employed would result in unequal ring intervals of the several engine cylinders. Such unequal firing intervals would be undesirable and would introduce into the engine increased torque variations that would be difficult to absorb or cope with.

The primary object of the instant invention is to provide a V-six engine having other than 60 degree V-angle and a suitable olf-angle crank pin or crank angle relationship necessary to satisfy the requirement for primary balance, and at the same time provide for equal firing intervals of the several engine cylinders.

Other objects of the invention will become apparent by reference to the following detailed description taken in connection with the accompanying drawings, in which:

Fig. 1 is a cross sectional view of a V-six internal combustion engine embodying the invention. Y p

Fig. 2 is a diagrammatic view showing the V-angle or block angle and crank pin or crank angle relationship of a V-six engine embodying the invention.

Fig. 3 is a diagrammatic plan view showing a preferred arrangement of cylinders of the V-six engine disclosed in Fig. l. f

Fig. 4 is a diagrammatic plan view showing the crankshaft of the V-six engine disclosed in Fig. l and the preferred arrangement of the main crankshaft bearings and crank pin bearings.

Referring now to the drawings wherein like reference characters refer to like and corresponding parts throughout the several views, Fig. 1 shows a cross sectional view of a V-six engine embodying the invention taken transversely through cylinders 1 and 2 as numbered in Fig. 3. The said V-six engine 10 includes the usual engine bloc-k 11 having cylinders 1, 2, 3, 4, 5 and 6 therein arranged in two banks 12 of three cylinders each, each cylinder bank 12 being disposed at an angle of other than 60 degrees with respect to the opposite cylinder bank, all as hereinafter described in detail. s Y

`The said engine 10 has a head 13 for each bank of cylinders 12 which includes the usual spark plugs 14, in-

Fr'ice take and exhaust valves 15 and 16, intake and exhaust manifolds 17 and 18, and other conventional engine elements of detail and design well known in the art. The engine intake and exhaust valves 15 and 16 are operated by a cam shaft 19 having a plurality of angularly related cams 20 thereon for opening and closing the said intake and exhaust valves through suitable valve operating mechanism 21 at proper timed relationship to established firing intervals of the said engine cylinders 1, 2, 3, 4, 5 and 6. The said engine cylinders are tired in a selected firing order by the spark plugs 14 and a conventional ignition system, not shown.

The said V-six engine 10 has a crankshaft 22 mounted in the engine block 11 on suitable main bearings 23, the said crankshaft 22 being provided with conventional crank pins 24, one for each cylinder, preferably located in the angular relationship indicated diagrammatically in Figs. 3 and 4. The said crank pins 24 are numbered l, 2, 3, 4, 5 and 6 in Figs. 2 and 4 to correspond to the cylinders numbered 1, 2, 3, 4, 5 and 6 opposite a bore of which each is located. The crank pin circle 220 upon which the crank pins rotate about the longitudinal center line of the crank shaft 22 is indicated by dot and dash lines in Figs. l and 2. Each cylinder 1-6 inclusive has a conventional piston 25 reciprocatingly mounted therein connected through a wrist pin 26 and connecting rod Z7 to a corresponding crank pin 1-6 inclusive of the crankshaft 22. Fig. 1 shows the aforementioned construction in detail for cylinders 1 and 2 and crank pins 1 and 2, crank pin locations 3, 4, 5 and 6 being indicated diagrammatically. Asso far described, the V-six engine 10 illustrating the invention is conventional, and may be of any detail and design selected by the engine designer. Accordingly, detailed description of the conventional elements of the said V-six engine 10 employed to illustrate the invention is unnecessary, and the novel features of the invention now may be described as follows.

In a conventional V-six engine, the center line of the cylinder bores of the two cylinder banks generally intersect at the longitudinal center line of the crankshaft, and the V-angle of the cylinder bores is 60 degrees or a multiple thereof to provide equal firing intervals of the cylinders. Also, in a conventional 60 degree V-six engine, the crank angle or the relationship between pairs of adjacent crank pins is 60 degrees.

In a V-six engine embodying the instant invention, the selected V-angle between the center lines of cylinder bores of the two cylinder banks is preferably made greater than 60 degrees, and the center lines of the said cylinder bores of the two cylinder banks of the engine block are disposed parellel to and offset from lines defining the said selected V-angl'e intersecting the longitudinal center line ofthe crankshaft.

If the selected V-angle between the cylinder bores of the two banks of cylinders is made 62 degrees rather than the normal V-angle of 60 degrees, an off-angle crank relationship between pairs of adjacent crank pins of degrees minus two times 62 degrees, or 56 degrees, would be necessary to satisfy the requirement for primary engine balance; however, such a relationship would result in a condition of unequal tiring intervals, which is highly undesirable and difficult to cope with.

ln the instant invention, equal firing intervals with such an olf-angle crank relationship as set forth above is obtained by offsetting the center line of the cylinder bores of the two banks of cylinders a distance X with respect to the lines defining the selected V-angle intersecting the longitudinal center line of the crankshaft.

If the engine has a stroke equal to S, and a connecting rod length equal to L, then the offset X of the said cylinder axis withv respect to the said lines definingl the said selected V-angle intersecting the longitudinal center line of the crankshaft would be:

X equals (L plus l/2S) sin.

Accordingly, the following relationship is necessary in an engine embodying the invention to obtain equal cylinder firing intervals and also satisfy the required condition for primary engine balance:

Alpha is the number of degrees of deviation of the selected block angle from 60 degrees.

Selected block angle equals 60 degrees plus alpha.

Crank angle of pairs of adjacent engine cranks equals 60 degrees minus 2 times alpha.

Cylinder bore offset equals (L plus 1/2S) sin. 31%)@ S equals length of stroke. L equals length of connecting rod.

With such an engine, vertical space can be saved, which is of utmost importance in many engine installations. Also, the increased crankpin overlap provided results in greater strength and stiffness throughout the engine. And further, increased crankcase compactness and reduction in engine weight is accomplished by virtue of a reduction in the longitudinal center line distance between the crankshaft and the camshaft occasioned by disposing the cylinder banks on an angle greater than the 60 degrees normally employed, which also favorably affects the camshaft drive life.

Although the invention has been described with respect to a V-six engine having a selected V-angle greater than 60 degrees, it is obvious that the invention is also applicable to V-six engines having a selected V-angle of less than 60 degrees, in which event the offset alpha would be an inwardly rather than an outwardly offset from lines defining the selected V-angle less than 60 degrees. It is to be understood that, although the invention has been described with reference to a particular embodiment thereof, it is contemplated that changes and variations thereof may be made within the scope of the invention as defined by the appended claims.

I claim:

1. A V-six engine including an engine block having cylinder bores therein forming two banks of three cylinders each arranged in V-relationship, a piston in each cylinder bore, a crankshaft including three pairs of crank pins arranged in 120 degree relationship, and connecting rods connecting said pistons to said crank pins with each of a pair of generally laterally opposite pistons connected through a pair of connecting rods to each of a pair of crank pins, the said engine having a selected V-angle between the center lines of the bores of the two cylinder banks of greater than 60 degrees, the center lines of the said cylinder berm of the two cylinder banks being disposed parallel to and offset outwardly from lines defining the said selected V-angle intersecting the longitudinal center line of the crankshaft, the said cylinder bore offset being equal to (L plus l/zs) sin. w

the crank pins of `each pair of crank pins being disposed 4 in an off-angle crank relationship equal to 60 degrees minus two times alpha, wherein Selected block angle equals 60 degrees plus alpha,

Alpha equals the number of degrees of deviation of the selected block angle from 60 degrees,

S equals length of stroke, and

L equals length of connecting rod.

2. A V-six engine including an engine block having cylinder bores therein forming two banks of three cylinders each arranged in V-relationship, a piston in each cylinder bore, a crankshaft including three pairs of crank pins arranged in degree relationship, and connecting rods connecting said pistons to said crank pins with each of a pairof generally laterally opposite pistons connected through a pair of connecting rods to each of a pair of crank pins, the said engine having a selected V-angle between the center lines of the bores of the two cylinder banks of less than 60 degrees, the center lines of the said cylinder bores of the two cylinder banks being disposed parallel to and offset inwardly from lines defining the said selected V-angle intersecting the longitudinal center line of the crankshaft, the said cylinder bore offset being equal to alpha 2 (L plus 1/2S) sin.

the crank pins of each pair of crank pins being disposed in an off-angle crank relationship equal to 60 degrees plus two times alpha, wherein 3. A V-six engine including a crankshaft and two banks of three cylinders each having their center lines disposed in parallel offset relationship with respect to lines defining a selected V-angle of greater than 60 degrees intersecting the longitudinal center line of the crankshaft of said engine, the said crankshaft including three pairs of adjacent crank pins arranged in 120 degree relationship, pistons each having a wrist pin reciprocatingly mounted in said cylinders, and connecting rods connecting the wrist pins of said pistons and crank pins of said crankshaft, the crank pins of each pair of crank pins being disposed in an off-angle crank relationship equal to 60 degrees minus two times alpha, and the said cylinder being offset outwardly a distance equal to alpha 2 (L plus 1/2S) sin.

wherein Selected block angle equals 60 degrees plus alpha,

Alpha equals the number of degrees of deviation of the selected block angle from 60 degrees,

S equals length of stroke, and

L equals length of connecting rod.

disposed in an off-angle crank relationship equal to 60 and intersecting the longitudinal center line of the crankdegrees plus two times alpha, and the said cylinder bore shaft, the said cylinder bore offset being equal to being offset inwardly a distance equal to l h (L plus 1/2S) sin. alp2ha a p a 5 (L plus 1/2'5') Sm' 2 the said crankshaft having one crank pin of each pair of crank pins spaced 120 degrees apart and the other crank pin of each pair disposed in olf-angle crank relationship from the adjacent said one crank pin equal to 60 degrees minus two times alpha, wherein wherein Selected block angle equals 60 degrees minus alpha, Alpha equals the number of degrees of deviation of the Selected blo k an l f 60 d Selected block angle equals 60 degrees plus alpha S equallS lengtl of stgrkod egrees Alpha equals the number of degrees of deviation :of the L equals length of connecting mi selected block angle from 60 degrees,

S equals length of stroke, and 5. A V-six engine including an engine block having l5 L equals length 0f Connectlllg IOd cylinder bores therein forming two banks of three cylinders each arrange in V-relationship, a piston in each References Cited m the me of thls Patent cylinder bore, a crank shaft including three pairs of crank UNITED STATES PATENTS T5225@ m 1 20 legree relationship an@ metmg 2 Re. 15,019 Landgraf Jan. 4, 1921 ctmg said pistons to said crank pins with each l 322 579 Kenen Nov 1919 of a pair of generally opposite pistons connected through l722950 Barkelj July l929 a pair of connecting rods to a pair of crank pins, the

said engine having a selected V-angle between the center FOREIGN PATENTS line of the bores of the two cylinder banks greater than 25 22,76() Great Britain v Oct. 5, 1912 degrees, the center lines of the said cylinder bores 154,824 Great Britain Dec. 9, 1920 of the two cylinder banks being disposed parallel to and 20,645 France July 13, 1918 oset outwardly from lines dening the selected V-angle (First add. to No. 481,076) 

